If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Clicking Sound w/ Cold Engine

I have a '92 525 with 165K. Recently I started hearing a clicking sound from the engine area that is louder when the engine is first started (cold) and gets quieter as the car warms up 2-3 miles until it's finally gone. It seems to occur in conjunction with pressing the gas pedal and accelerating. Taking your foot off the gas will stop the noise. I don't believe it's anything related to tires, wheels, or transmission. Depressing the gas pedal in neutral will not cause the sound. It seems to occur when the engine is under the stress of acceleration. It's a definite click that increases in cadence as the vehicle accelerates. I'm thinking it's some type of solenoid that is supposed to open and close, but is worn and now causing the noise. Any ideas?

Re: Sure it's not valve hydraulic tappets?

Floyd, thanks for your response. I'm fairly certain it's not valve tappets. On a cold start with the hood open, I revved the engine and can't hear the noise. It only occurs when I depress the gas pedal while in drive. The harder I press the pedal the louder it gets and the frequency of the clicking increases. Easing up on the pedal causies it to quiet. Depressing the pedal in neutral won't do it. After a mile or two the sound is completely gone. Very strange...

Re: Sure it's not valve hydraulic tappets?

My hydraulic tappets clack like crazy upon startup especially when my oil is even slightly low. It goes away within 10 seconds. I use Lubromoly MOS2 oil additive and it really helps. John, your problem is certainly not the tappets. A good place to check though would be the VANOS system, as this can also make tapping noises and may do it more under stress than not. I'm not a mechanic, so this is just a suggestion. Oil to the VANOS system is critical, and the tube that carries oil to it can be faulty.

Sometimes I wonder if 20W50 oil is too heavy for high mileage engines. My car seems to like 15W40 or 10W40 better, as the tappets don't complain as much upon start up.

drivetrain?

Because it doesn't happen in neutral it's probably drivetrain related. Maybe a heat shield that is slight loose rubbing on something rotating (like driveshaft), maybe something in the clutch that rubs and needs to expand a little bit (which would happen when it gets warm) to stop ticking.